i wonder that, too, WF. i guess it depends. in the example you provide, i see it happening as just another blasse shootout, guy on the top of the brothel grabs his chest and falls off screen, etc.. if, however, that guy lands on a sign standing out from the side of the building, i'd want to mention that. actually, when i get around to writing something like that, i'll probably do a combination. like in a novel, no one wants to read extended blow-for-blows, but you'd want to put in the highlights.
i'm just experimenting right now with writing a script. i still need to read a whole lot because i'm not sure exactly how it should be written. for instance, i've got a guy who sticks his head out the car window to shoot, so i guess that gets a new slugline? that is, can i imply this without having to write in a new slugline?
so far, i'm being rather light on description. a '35 black Cadillac is expressed as just that. do i need to add some details so the reader can visualize it better, or let it stand? guess that's where reading scripts comes in handy, eh? (yeah, yeah, i know i need to read more, so this is kind of a rhetorical question.) do people who read scripts need something beyond 'a dusty, quiet town in the 30's panhandle', or do they want to read about the lay-out of the town, the kinds of stores there are, what the people are dressed in, etc.?